Xcode and SVN: can't rename my class -> Error: 155007 (Path is not a working copy directory)

I get the following error, if I try to rename my class:

Error During Rename

Error: 155007 (Path is not a working copy directory) Description: Path 'xxx/Classes/MyClass.h' is not a directory

The renaming looks like this: MyClass.h -> MYClass.h

Perhaps that is the problem?

I've made an initial import to my SVN directory. This is working so far (deleting, committing, etc.) The only thing it can't is renaming a class.

I tried:

4.Now delete your local copy (or move it to another location just in case).

5.Finally CHECKOUT the project from subversion (this will create the subversion .svn folders, …).

6.Reselect the subversion repository for this project.

7.Commit the entire project.

There is also no build directory in the SVN directory. The one thing which stands out is that I can't see any .svn folder. I'm using Xcode 3.2.3. The file I'm trying to rename/refactor is in the classes folder. I tried to delete a file from the classes folder and it worked!

I read this. I also found a similar problem. But there is no solution available so far.